The goal of this project is to develop functional magnetic resonance imaging (fMRI) applications for the assessment of brain-related visual pathology in humans. The work will address a critical clinical need for sophisticated methods of preoperative assessment that can provide a precise, detailed picture of the relationship between a site of focal pathology and the functional status of surrounding visual cortex. Such information can be essential for planning surgical treatment that optimally removes or repairs a pathology (e.g. tumor) yet avoids significant vision loss. Bioengineering will be used to develop, optimize and validate methods for mapping visual cortex function in and around a site of pathology and relating disturbances of cortical function to disturbances of vision. An interactive physician interface will allow the clinician to view the results of these analyses in an easy to use format and will permit simulation of surgical strategies with immediate display of the potential impact on vision. The patient will be able to experience a simulation of the expected vision loss, thereby allowing both physician and patient to evaluate the proposed treatment. The developed tools will also be applied to hypothesis-driven experimentation designed to characterize the fundamental interrelationships of focal pathology, cortical function, and visual perception both acutely and as they evolve over the course of treatment and recovery. The cortical effects of different pathologies including stroke, AVM's, epileptic foci and tumors will be compared and contrasted. The relative contributions of different neural mechanisms to recovery of visual function will also be tested. The ultimate goal of this project will be to provide health-care professionals and patients with new information they can use to evaluate different treatment options and predict the potential for an optimal outcome. The new brain maps of pathology vs. function should make surgical procedures, once considered too risky, a viable option. The experimental work will establish principles interrelating cortical pathology, functional impairment, and recovery that can be extended too much, if not all, of the brain. Finally, this project will provide a useful model for the translation of basic neuroscience research into clinically useful applications.